What is the normal (expected) idle under normal weather conditions. I think my Blazer idles too high even in the summer days. The current readings are about 1000-1100rpm cold and 600-700rpm warm. It doesn't sound too much but subjectively it just runs too high.

  • I checked vacuum leak several times with different techniques but never found one
  • Checked and cleaned IAC and throttle body, both were fine too.
  • 2
    If you start the engine cold, and it idles 1100rpm -> 700rpm in ~5 mins (fast idle, to warm up quicker), then you should not worry.
    – oryades
    Aug 16, 2017 at 7:32
  • Let me perhaps add one finding. Right after crank up (cold start), the engine idles lower (about 800rpm), then about in one second it goes to the 1000-1100 range and very slowly lowers the RPM to the target 600-700. It doesn't matter on outside temperature or humidity at all.
    – Jan
    Aug 22, 2017 at 6:37

1 Answer 1


A v8 once warm can easily idle comfortably around 600rpm (in good condition...), my 3.5litre v8 did that all the time once warm (but not fully up to temp...).

  • Even my small 1.33 litre inline-4 idled in some cases below 600RPM.
    – juhist
    Aug 16, 2017 at 12:06
  • not necessarily as smooth though - inline 6's are also very smooth, but 4 cyl not so...
    – Solar Mike
    Aug 16, 2017 at 13:49

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